Friday, September 29, 2006

How we all laughed when Prince Charles revealed years ago that he spoke to plants. "They respond I find," he said in one of his most infamous exchanges with reporters. Well it seems the future King of England may have been on to something. A new study has presented the strongest evidence yet that grasses and flowers can actually communicate, if not with humans then at least with each other. At the heart of the study, conducted by Justin Runyon and colleagues at Pennsylvania State University and reported in today's Science , is an unremarkable looking weed called dodder. Dodder is a parasite which makes up for its inability to photosynthesise very well by wrapping itself around the stems of other plants and sucking out their nutrients. The yellow weed is bad news for farmers in particular, hence dodder's nickname strangle-weed or witches' shoelaces. The study looked at the way the pesky parasite finds its victims and ran an experiment in which dodder plants were given a choice of plants to wrap themselves around. It turned out the weed favoured some plants over others. While tomato plants, for instance, were popular targets others, such as wheat, were not. Looking deeper the scientists found an explanation for this: wheat emits an airborne chemical (or volatile) that somehow repels the dodder. In effect, it shouts "stay away from me". They think the tomato plants may have been sending the opposite signal out, releasing volatiles that say "come and get me". Previous studies have suggested that plants under siege from herbivorous insects send messages to other plants telling them to boost their chemical defences before they too are infested, but this is the clearest evidence yet that plant-to-plant chatter really does exist. "The results go a long way toward convincing people that plant-plant interaction via volatiles is a real phenomenon," says Eran Pichersky, an evolutionary biologist at the University of Michigan, Ann Arbor.

Wednesday, September 27, 2006

An excellent post on the very smart science blog Pharyngula adds an intriguing possibility to the argument about which are smarter - cats or dogs? Pharyngula explains in sometimes brain-frazzling detail how the domestic cat's lack of interest in sweets and candy is defined by its genes. A mangled mutation of a taste receptor gene that normally registers the effect of sugary tastes has effectively left the gene dead and unable to function. Basically, your kitty can't experience sweets in the same way we humans do for instance, so they generally give them a wide berth. He also suggests this has happened through evolution and is common to other members of the cat family, like lions and tigers. Now this makes me wonder whether this is proof that cats are smarter than dogs, at least when it comes to evolving successfully. Sweets, and in particular, chocolate can be highly dangerous to animals. The large doses of toxic theobromine in dark and baking chocolates can send the canine system in particular into overdrive, causing increased urination, over-excitement, muscle tremors, increased heart rate and - in the worst case scenario - fatal cardiac attacks. Yet what happens when you lob a tasty-looking chunk of chocolate in a dog's direction? Yep, the concept of death by chocolate is completely alien to it. Instead it, er, wolfs the stuff down much like its much more resilient ancient ancestor probably would. So why haven't dogs - like cats - learned any better? Given the way we've tinkered with almost every aspect of their physiognomy in the name of selective breeding, should we take some of the blame?

Monday, September 25, 2006

Scientists seem to have confirmed what anyone with half an ounce of taste has known for a long time - techno music is to be avoided at all costs. A report, in Seed Magazine, reveals how monkeys shun the dire, monotonous drone of electronic music for more soothing sounds, such as lullabies. The study's authors, Josh McDermott, a perceptual scientist at MIT, and Harvard evolutionary psychologist Marc D. Hauser, had found in earlier tests that tamarin and marmoset monkeys can tell the difference between different types of music. They took this a step further and tested which music they preferred. By building a maze with two navigable paths and two speakers at either end, they were able to test which type of music attracted monkeys. Given a choice betwen a lullaby and silence, the monkeys headed down the maze that led to the silent speaker. Given the choice between a lullaby and German techno music, however, they chose the quieter tones of the lullaby. "The continuity of the melody of a lullaby is something that is designed to calm," Hauser said. He also suggested the monkeys' choice of slower tempos might be tied to "ancient evolutionary roots". The pair's results are to be published soon in the journal Cognition. This isn't the first time animals' musical tastes have been observed. In a less scientific environment, for instance, farmers have discovered that cows produce more milk to Beethoven than they do to pop music. Playing the 80s band Bananarama actually reduces their productivity. Another scientist, however, is cautioning against getting too carried away about music-loving creatures. "These experiments clarify that the animals can in fact show preferences in response to music," says Erin Hannon, a psychologist and expert in music perception at Harvard. "Yet, it also shows that these animals just aren't generally very interested in music."

Love is a risky business, just ask the Utah prairie dog. A recently reported, new study of the cute-looking critters reveals that males pay a high price for pursuing females during the species' brief, 17-day long breeding season each year. The prairie dog is hunted by a range of predators, including foxes, badgers, eagles, goshawks and coyotes. As a result the endangered creatures spend their lives conducting a high-risk game of hide and seek with their pursuers. The survey of a 200-strong colony of praire dogs in Bryce Canyon National Park suggests their hunters may hold the upper hand. Predation rates soared during the breeding season, with ten male prairie dogs falling victim to foxes or goshawks, far more than during the rest of the year. Scientists think this suggests the predators know the male prairie dogs will show themselves out in the open more during this period, possibly to impress females with their macho behaviour. They have learned to lie in wait, then capitalise. The study is being seen as a significant breakthrough in proving how animals carefully select their hunting grounds. "This is by far the best documentation and quantification of selective predation," says Jerry Wolff, a behavioral ecologist at St. Cloud State University in Minnesota. The study was carried out by behavioral ecologist John Hoogland of the University of Maryland Center for Environmental Science in Frostburg and will be reported in next month's American Naturalist.

Wednesday, September 20, 2006

Birds stumble over their words too, or so a new study suggests. Warbling songbirds each have their own subtle signature tune which they develop at a young age and use throughout life to identify themselves. But, rather like humans who struggle to hold their voices with others singing around them, birds need to be able to hear each note they are producing to keep in perfect pitch. And if they are interrupted by the sound of their own song being repeated back to them, they can completely lose their way reverting to a stammering babble. A rather cute New Scientist recording of a finch interrupted by the sound of its own song being repeated back to it reveals what happens. One of the authors of the study compares the effect of his experiment with one of us losing our thread when we hear our voice echoed down a transatlantic telephone line. “We think that the dependence on auditory feedback is similar in humans and songbirds,” says Jon Sakata of the University of California in San Francisco, whose results are published in the Journal of Neuroscience.(Reference: DOI: 10.1523/jneurosci.2027-06.2006) Sakata thinks his study supports the theory that human stuttering is caused by the abnormal processing of this kind of feedback.

Monday, September 18, 2006

Scientists at work in uncharted coral reefs off Papua New Guinea have discovered a treasure trove of new animal life. According to Conservation International, two dozen new species of fish, as well as eight previously unknown types of shrimp and twenty unique forms of coral have been found in the Bird’s Head Seascape, which stretches for 180,000 sq km (70,000 sq miles) on the north western end of PNG. By far the most fascinating of the research team's discoveries is the epaulette shark, pictured above. The 1.2 metre (4ft) long creature walks along the sands of the ocean floor using its muscular pectoral fins as legs. Other finds include a shrimp with a striking resemblance to a praying mantis and a male wrasse fish with a highly colourful courtship ritual: when courting females its body turns from a rather dull grey to a spectacular blaze of yellow, blue and purple. The research team are convinced they have only scratched the surface of the area's scientific riches, however. The "coral triangle" is thought to be home to at least 1,200 species of fish and almost 600 species of reef-building coral - three quarters of the world's known totals for these species. “It’s one of the most stunningly beautiful landscapes and seascapes on the planet,” Mark Erdmann, a senior adviser of Conservation International who led two surveys to the area earlier this year, is quoted as telling The TImes. “Above and below water, it’s simply mind-blowing.”

Friday, September 08, 2006

Here's an intriguing - and if you are male, worrying - thought. Is global warming a dastardly scheme cooked up by females so they can take over the planet? A new study of reproduction in one creature affected by rising temperatures and sea levels - the Caribbean hawksbill turtle - has raised the sinister possibility. (Sort of.) As with other animals, such as lizards and snakes, the sex of a turtle's hatchling will depend on the temperature its eggs are kept during incubation. In general, the cooler the egg is kept, the more likely the baby is to be male. The hotter the egg, the more likely it is to be female. With this in mind, the hawksbill turtles chooses different incubation grounds for male and female eggs, dividing eggs roughly equally among the two sites to maintain a balanced population. To produce males they lay their eggs above the high tide marks on beaches where, in the past, at least, the shade of the natural forests have kept temperatures cooler. However, rising sea levels and temperatures - as well as deforestation by humans - has reduced the number of cool spots for the turtles to lay their eggs. As a result, or so the survey reported in Science magazine concludes, the hawksbill population is becoming more and more dominated by females. If things carry on like this, the poor male turtle will soon be completely over-run by his female counterparts. We have yet to see evidence of how lizard and snake populations are changing, but it's a safe guess they may well be experiencing the same female bias. Where will it end? And is there a female hand at work in all this? Don't human mums produce more CFCs?

Wednesday, September 06, 2006

We knew chimps were smart, but who realised they had such impeccable manners? Amazing new film footage, part of a study just published in Current Biology, shows a group of chimps crossing a busy track that had recently opened in a forested area of Guinea, west Africa. As they approach the road, the three males in the twelve-strong pack, adopt positions at the front and the rear. While the one at the front checks the road to make sure the coast is clear the other two leads the five women and four youngsters to safety, also checking for traffic as they go. Researchers Kimberley Hockings at Stirling University and Tetsuro Matsuzawa at Tokyo University reckon the roles reflect the chimps positions within the hierarchy. The Alpha Male of the group, Yolo, adopts a position at the back of the pack in most cases. "Adult males, less fearful and more physically imposing than other group members, take up forward and rearward positions, with adult females and young occupying the more protected middle positions," Hockings and Matsuzawa write. Chimps have been seen working together to extract food in the past, but the pair think their study offers a unique, new insight into how groups of primates work together to solve more complex problems. "Although humans themselves are not predators of these chimpanzees, we propose that road-crossing, a human-created challenge, presents a new situation that calls for flexibility of responses of chimpanzees to variations in perceived risk," they wrote.